Ho3+ single-doped and Ho3+/Yb3+ co-doped tellurite glasses with the composition of TeO2-ZnO-Na2O were prepared by melt-quenching method.The intensity parameters Ωt(t=2,4,6),spontaneous radiative transition rate A,fluorescence branching ratio β and radiative lifetime τrad of Ho3+ are calculated based on the measured absorption spectra with the Judd-Ofelt theory.The influence of Yb3+ doping on the Ho3+ upconversion emission is investigated through the measurement of upconversion spectra,and the energy transfer mechanisms between the Yb3+/Yb3+ and Yb3+/Ho3+ ions are analyzed in detail.The results show that the upconversion emission of Ho3+ ions under 980 nm diode laser excitation is mainly the result of energy transfers:first the resonant energy transfer from Yb3+ to Yb3+ ions,and then the one and two phonon-assisted nonresonant energy transfer from Yb3+ to Ho3+ ions.The energy transfer coefficient and phonon contribution for the above energy transfer process are calculated and analyzed.Meanwhile,the absorption,emission cross-sections and gain coefficient of Ho3+:5I7→5I8 transitions are calculated.The research shows that the Yb3+/Ho3+ co-doped TeO2-ZnO-Na2O glass is a promising host material applied for upconversion laser and 2.0 μm-band solid laser.